netfilter: x_tables: Update remaining dereference to RCU

stable inclusion
from linux-4.19.167
commit 954cc63f5d49851073c508d596af054da59505ab

--------------------------------

commit 443d6e86 upstream.

This fixes the dereference to fetch the RCU pointer when holding
the appropriate xtables lock.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: cc00bcaa ("netfilter: x_tables: Switch synchronization to RCU")
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>

Signed-off-by: Aichun Li <liaichun@huawei.com>
reviewed-by: wangxiaopeng <wangxiaopeng7@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>